The present invention is directed to musical instruments, commonly known as flutes, that are based on the operation of an air reed. The sounds produced by a flute arise due to the impingement of air on an edge, known as the air reed, causing the air to oscillate as it passes into a sound chamber, producing an audible tone. The two primary categories of flutes include tubular flutes (for example, those of the modern Boehm flute family (i.e., the orchestral flute family including C-flutes, piccolos, alto flutes, bass flutes, etc.), the recorder, the tin whistle, the quena, the nay, the shakuhachi, etc.) and enclosed vessel flutes (such as the ocarina). As used herein, the term “flute” does not encompass enclosed vessel flutes.
Tubular flutes generally employ sound chambers open at both ends, wherein the embouchure hole is one of the end-openings. This is in contrast to other woodwind instruments, e.g., the clarinet, saxophone, oboe etc., wherein the mouth of the player encloses and seals one end of the central bore of the instrument, forming a sound chamber open at only one end. The sound chamber of a tubular flute is relatively long and slender, and is shaped (or substantially shaped) like a tube or a truncated cone, and may optionally comprise one or more tone holes in the wall of the sound chamber, i.e., in the side wall of the instrument. The most well-known flutes in Western cultures are the orchestral transverse flutes, or Boem flutes, which comprise an embouchure hole in the side wall of the sound chamber rather than at the end of the tube as in an end blown flute such as a nay or shakuhachi. The placement of the embouchure hole requires the orchestral flute to be supported laterally to the player's side, at an approximately 90° angle relative to the vertical formed by the player's torso. Maintaining the constrained horizontal position is especially tiresome on the hands, arms and neck. After long periods of playing, it may become difficult to move the fingers properly to precisely control the finger holes and keys. Accordingly, repeated efforts have been made to redesign the transverse instrument and/or head-joint thereof such that it may be played in a vertical position (see e.g., U.S. Pat. Nos. 4,422,364; 3,888,154, each of which is hereby incorporated by reference in its entirety). Moreover, the tonality of the transverse flute is known to be adversely affected by placement of the embouchure hole and resulting streamlines of blown air entering the flute.
In transverse flutes, the air is blown against the air reed (which is formed from a section of the embouchure hole), enters the embouchure hole and is forced into a spiral course within the sound chamber at a right angle to its direction of entry. Part of the air entering the sound chamber is deflected towards a closed section of the sound chamber (i.e., toward the cork or stopper of a traditional Boem flute) and from there is again deflected back toward the embouchure hole and the remaining open end of the sound chamber (i.e., the portion of the sound chamber comprising one or more tone holes). This path creates a turbulent air-stream within the flute in the area of the embouchure hole, recognized to negatively affect the tonality of the flute. For example, the turbulent air-flow has been ascribed to cause a “hissing sound” (see, e.g., U.S. Patent Application Publication No: 2004/0255754, herein incorporated by reference in its entirety) or to cause out of tune progression into the higher harmonics (see, e.g., U.S. Pat. No. 594,735, herein incorporated by reference in its entirety).
Efforts to improve the air-flow within the sound chamber of transverse instruments in the area of the embouchure hole, and to thereby improve the tonality of the instrument across all octaves, have included redesigning the interior of the sound chamber to attempt to direct airflow in a laminar fashion (see, e.g., U.S. Pat. Nos. 5,261,308 and 5,435,221, each of which is hereby incorporated by reference in its entirety), redesigning the shape of the sound chamber in an attempt to promote laminar flow (see, e.g., U.S. Patent No.: 2004/0255754), redesigning the shape of the sound chamber and placement of tone holes (see, e.g., U.S. Pat. Nos. 4,714,000; and 6,259,010, each of which is hereby incorporated by reference in its entirety), and moving the embouchure hole to the end of the sound chamber (see, e.g., U.S. Pat. Nos. 444,830; and 594,735 each of which is hereby incorporated by reference in its entirety). The instant patent encompasses a solution to the turbulent flow and/or playing position considerations by, in effect, placing the air reed at the end of the sound chamber, forming an end-blown flute.
End-blown flutes traditionally encompass non-western flutes (such as, but not limited to the nay, the quasaba, the shakuhachi, e.g., a “shakuhachi-type flute”) and, in certain embodiments, fipple flutes (e.g., the recorder, the tin whistle). To play an end-blown, shakuhachi-type flute (e.g., wherein the embouchure hole is formed from the open end of the central bore of the instrument and wherein the air reed is thus formed from a section of the side wall of the instrument) the player focuses air directly over the air reed using the lips. In contrast, fipple flutes employ an airway to focus the air over the air reed. However, relative to traditional Western transverse flutes, either fipple-type or shakuhachi-type end blown flutes suffer from weaknesses in playable tonal range, in particular, in the range of tones they are able to be played harmonically, or in-tune. For example, a flute designed to emit a strong lower register is often quite shrill in the upper register(s) because the player is forced to blow relatively hard to obtain upper register notes. Similarly, in such flutes the upper octaves tend to be out of tune in relation to the bottom octave, and higher notes can be difficult to reach. These weaknesses are corrected in the transverse flutes by extending and enclosing the tubular sound chamber beyond the embouchure (and, thus, air reed), effectively placing the air reed and embouchure in the side wall of the sound chamber, and forming an acoustic air space and fluid air space on opposite sides of the air reed (see, e.g., Arthur H. Benade Fundamentals Of Musical Acoustics, (Oxford University Press, New York, N.Y. 1976). Prior to the present invention, however, attempts to redesign an end-blown flute to encompass an acoustic air-space have failed to address the problem of turbulent air-flow at the embouchure hole. For example, U.S. Pat. No. 444,830 teaches an end blown flute comprising at least one lateral tuning chamber on the side of the air reed. The positioning of the chamber(s) places it (them) at least partially in the path of the blown air, creating disruption of the air flow as the air passes the chamber(s) before spreading downward to fill the open sound chamber. Accordingly, the instant invention addresses the tonality/harmonic weaknesses of end blown flutes in general.